Waste management group Biffa has seen more than a fifth of shareholders vote against the re-election of chairman Ken Lever amid concerns over the number of board roles he holds.

The UK’s biggest collector of commercial waste said 20.5% of investor votes did not support his re-election at its annual general meeting.

While his re-election was supported with a majority of votes in favour, Biffa pledged to consult with disgruntled shareholders to “understand their views with respect to multiple board commitments” held by Mr Lever.

“The board is confident that Mr Lever discharges effectively his role as chairman, notwithstanding his other board commitments,” the group added.

Mr Lever was appointed chairman in March last year following the sudden death of his predecessor, Steve Marshall, in September 2017.

Mr Lever, who has served on the board of Biffa since September 2016, is also chairman of professional services firm RPS Group and a non-executive director of car dealership Vertu Motors, software firm Blue Prism and asset manager Gresham House.

Details of investor protest came after Biffa confirmed that trading was in line with expectations and said it continues to “make progress” with its growth strategy.

But full-year results last month showed that pre-tax profits for the year to March 29 fell 44% to £21.5 million.

Chief executive Michael Topham – who took over recently when former boss Ian Wakelin stepped down – said on unveiling the figures that Biffa plans to continue buying up smaller rivals, having snapped up seven businesses in the last year alone.

It has bought 17 rivals since listing on the stock market in October 2016.